In 1988, our unit introduced an innovative and pioneering tool
In 1988, URTAL launched an experimental mini cheese plant with several key objectives:
- To produce small-format cheeses that replicate the characteristics of industrial cheeses;
- To enable the modification of technological parameters during production, based on experimental conditions;
- To conduct national and international research programs, replicating various cheesemaking processes under controlled conditions, with the aim of better understanding the impact of specific factors on cheese quality.
To achieve these objectives, the mini cheese plant was equipped with a data acquisition and control system, which allowed for the programming and execution of specific tasks (such as vat work and cheese pressing) while recording essential data, including milk temperature, coagulation time, vat heating curves, and pressing temperature and force. Initially, the mini cheese plant was outfitted with four 12-liter stainless steel vats for experimentation, as well as ripening cellars with precise temperature and humidity control.
However, over time, it became clear that the 0.2 to 1 kg cheeses produced in the 12-liter vats were insufficient for studying the evolution of microbiological and biochemical characteristics during ripening, as multiple samples were required. Additionally, the cheese quantity was not adequate for sensory analysis with a 10–12-person panel. To address these issues, we acquired four 40-liter stainless steel vats in 2001, followed by four 100-liter stainless steel vats in 2006. Yet, stainless steel vats only partially reflected the equipment used by traditional cheesemakers. Recognizing the need to better mirror traditional practices, we added four 100-liter copper vats in 2012, which are commonly used by producers in traditional cheesemaking.
A Tool That Goes Global
This experimental mini cheese plant achieved notable international recognition. Between 1990 and 2000, three units were exported to Canada (Laval University), Italy (Zootechnical and Dairy Institute of Sardinia), and Egypt (University of Alexandria).
Our Journey Toward Scientific Recognition
Since its creation in 1988, this versatile experimental tool has enabled research projects to be carried out on a wide range of topics, benefiting both traditional and industrial sectors, or both.
Period 1988-2000: The Role of Raw Milk in Cheesemaking
The early research conducted using the experimental mini cheese plant (equipped with 12L vats and producing 0.2 kg cheeses) focused on understanding how the thermal history of milk (including storage, maturation, and heat treatments) impacted the sensory characteristics of uncooked pressed cheeses (PhD thesis by E. Beuvier, 1990). These studies combined heat treatments and milk microfiltration, enabling to separately assess the effects of milk microflora and enzymatic systems on proteolysis and flavor development during cheese ripening.
In the 1990s, the use of raw milk for cheesemaking became a topic of debate, particularly regarding its preservation for cheesemaking processes. To answer this question, we aimed to scientifically demonstrate the role of raw milk microflora in shaping cheese characteristics. Using the experimental mini cheese plant, we compared cheeses made from raw milk, pasteurized milk, and microfiltered milk. This allowed us to evaluate how different milk treatments affected the characteristics of ripened cheeses (both cooked and uncooked-pressed cheeses weighing 1 kg). Our findings revealed that eliminating the raw milk microflora through pasteurization or microfiltration resulted in a decrease in secondary proteolysis, fermentation processes, and changes in the volatile compounds produced during ripening. As a consequence, the cheeses displayed less intense aromas and overall different organoleptic qualities (Demarigny et al., 1996; 1997; PhD thesis by Y. Demarigny, 1997; Beuvier et al., 1997; Buchin et al., 1998; Buchin & Beuvier, 2000). These studies not only supported the case for raw milk cheeses but also contributed to the national and international recognition of our expertise in raw milk cheese research, making us pioneers in this field and influencing other European research teams.
During this period, we also focused on terroir-specific lactic starters. We isolated lactic acid bacteria strains from milk, natural starters, and Comté cheeses at the beginning of ripening, characterizing them for their acidification and proteolysis abilities. These strains were tested in the mini cheese plant (12L vats, 1 kg cooked-pressed cheese) (PhD thesis by Y. Bouton, 1992). This work led to the selection of about fifty strains of thermophilic lactic acid bacteria, now used by two-thirds of Comté cheesemakers. Additionally, we investigated the role of lactococci starters added at the beginning of production in the maturation of milk destined for Comté cheese. Mini-production trials in the 12L vats (1 kg cooked-pressed cheese) demonstrated that lactococci influenced the growth of thermophilic lactobacilli (reducing their lag phase) and, to a lesser extent, the growth of thermophilic streptococci during the early pressing stages (PhD thesis by S. Jeanson, 2000; Jeanson et al., 2003), contributing to the development of starter culture cocktails for the Comté cheese sector.
Period 2001-2010: Cheese as a Health Food
In addition to research on the sensory quality of cheeses, URTAL expanded its focus during this period to explore the nutritional and health benefits of cheese. Collaborating with other research teams, including UMR STLO-Rennes, CHU-Besançon, and the SERF Unit at the University of Franche-Comté (now UMR Chronoenvironnement), URTAL contributed to several key projects.
One major initiative was the European Truefood project, which aimed to enhance the sensory, nutritional, and health qualities of European traditional food products and to innovate in their production methods. As part of this effort, URTAL produced pressed cooked cheeses (10 kg, using 100 L stainless steel vats) in its experimental mini cheese plant. A selection of thermophilic starters was used to control sensory characteristics and improve the nutritional and health value of the cheeses, particularly their bioactive peptides, vitamins, and antioxidants (M. Charlet thesis, 2008; Charlet et al., 2009; Buchin et al., 2012). The research showed that different combinations of thermophilic starters could influence the level of antihypertensive peptides in the cheeses, with production being particularly dependent on vat heating temperature (Gagnaire et al., 2009).
At the same time, URTAL contributed to a project investigating the effects of consuming raw milk cheeses on gut microbiota and the associated immunological responses, particularly during antibiotic treatments. This collaborative project with CHU Besançon and the SERF Unit involved producing 10 kg pressed cooked cheeses (100 L vats) for study participants (Bertrand et al., 2007; Beuvier et al., 2008). The results highlighted a beneficial impact of cheese consumption on the human gut microbiota.
Additionally, URTAL worked with traditional cheese producers to improve the sanitary quality of raw milk cheeses. The project aimed to assess the conditions of production, control, and prevention of staphylococcal enterotoxins in raw milk cheeses. Under controlled cheese-making conditions, the project evaluated the potential for enterotoxin production based on the phenotypic and genotypic diversity of Staphylococcus aureus strains. Uncooked pressed cheeses (1 kg) simulating three different cheese-making technologies were produced in 12 L vats (H. Lamprell thesis, 2003). The findings showed that the growth and enterotoxin production of S. aureus were influenced by the bacterial strain, enterotoxin type, and specific manufacturing conditions, including the rate of acidification.
Period 2011 – 2023: Milk Properties and Cheese Transformation
During this period, we focused on how cow diets impact the nutritional profile of milk, its suitability for cheese-making, and ultimately the sensory characteristics of the cheese. These studies were conducted in collaboration with UMR PEGASE in Rennes (Research Unit for "Physiology, Environment, and Genetics for Animal and Livestock Systems").
As part of this work, URTAL produced pressed cooked cheeses (4 kg, 40 L vats) in the experimental mini cheese plant, using milk from cows fed various diets, including rapeseed, flax, and microalgae, either individually or in combination (Hurtaud et al., 2012; Hurtaud et al., 2014; Hurtaud et al., 2015a; Hurtaud et al., 2015b; Vanbergue et al., 2018). In addition to the nutritional benefits provided by these feed ingredients, we were able to provide technological recommendations to optimize milk for cheese production. Furthermore, several considerations were raised regarding the impact of these feeds—whether used alone or in combination—on the sensory characteristics of pressed cooked cheeses.
With funding from the ANR, we developed a method to measure redox potential (Eh) during the cheese-making process (1 kg pressed cooked and uncooked cheeses, 12 L vats). This involved creating a system to monitor the Eh from the milk in the vat through to the cheese under press. We validated these measurements by tracking the kinetic evolution of Eh and its values at the beginning of ripening, using both mesophilic and thermophilic lactic acid bacteria (Cachon et al., 2015; Petitpas et al., 2018). Since redox potential affects microbial growth and activity, our findings open exciting new avenues for research, particularly in cheese aroma formation (Buchin et al., 2021) and the control of undesirable microbiota (E. Munier thesis, 2023).
Thermophilic lactobacilli are essential components of the lactic starters used in the production of raw milk pressed cooked cheeses, contributing to the acidification of both milk and curd, as well as the proteolysis of the cheese. We demonstrated how different strains of Lactobacillus delbrueckii subsp. lactis used in starters influence the production of volatile compounds that can impact the flavor profile of pressed cooked cheeses (40 L vats, 4 kg cheeses) (Buchin et al., 2017). The mechanisms behind these effects are still under investigation.
Fluctuations in the diet of cows in organic, low-input grazing systems, along with varying calving patterns, lead to changes in the milk’s composition at both the macro- and micro-constituent levels. These variations affect the milk’s suitability for cheese-making. Choosing the right cheese-making technologies and fine-tuning the production process for a specific cheese variety enables the optimal utilization of milk in cheese production. Since 2019, URTAL, in collaboration with INRAE’s ASTER-Mirecourt and UMRF-Aurillac units, has been researching the variability in the physico-chemical and microbiological composition of organic milk, and how technological choices in cheese-making can optimize the quality of cheeses made from this milk (Beuvier et al., 2023).
Références bibliographiques
- Bertrand X., Dufour V., Million L., Beuvier E., Gbaguidi Haore H., Piarroux R., Vuitton D.A., Talon D. 2007. Effect of cheese consumption on emergence of antimicrobial resistance in the intestinal microflora induced by a short-course of amoxicillin/clavulanic acid. Journal of Applied Microbiology 102, 1052-1059.
- Beuvier E. 1990. Influence du traitement thermique du lait en fonction des conditions de stockage et de maturation sur la flaveur d’un fromage à pâte pressée non cuite. Thèse de Doctorat en Sciences de la vie, Université de Franche-Comté, 242 p.
- Beuvier E., Berthaud K., Cegarra S., Dasen A., Pochet S., Buchin S., Duboz G. 1997. Ripening and quality of Swiss-type cheese made from raw, pasteurized or microfiltered milk. International Dairy Journal 7, 311-323.
- Beuvier E., Dufrene F., Duboz G., Faurie F., Lefier D., M.H. Duployer M.H., X. Bertrand X. 2008. Lactic and propionic acid bacteria survive gastrointestinal transit of healthy volunteers treated with amoxicillin-clavulanic acid consuming raw milk cheese. 5th Symposium on Cheese ripening, 9-13 march, Bern.
- Beuvier E., Rolet-Répécaud O., Barbet P., Buchin S., Brunet L., Puech T. 2023. Systèmes d’élevage et aptitude à la transformation fromagère des laits biologiques : entre stratégies d’éleveurs, itinéraires technologiques et qualités des fromages. Séminaire METABIO, 21-22 mars 2023, Saint Malo, France
- Bouton Y. 1992. Caractérisation approfondie sur minifromages de l'activité proteolytique de souches et associations de souches de bactéries lactiques thermophiles utilisées en fabrication de comté. Relation avec les caractéristiques organoleptiques. Thèse de Doctorat en Microbiologie, Université de Nancy, X p.
- Buchin S., Beuvier E., 2000. La spécificité des fromages au lait cru: le rôle de la microflore naturelle du lait. 7èmes Rencontres Recherches Ruminants, Paris 6-7 Décembre, 361-363.
- Buchin S., Delague V., Duboz G., Berdagué J.-L., Beuvier E., Pochet S., Grappin R. 1998. Influence of pasteurization and fat composition of milk on the volatile compounds and flavor characteristics of a semi-hard cheese. Journal of Dairy Science 81, 3097-3108.
- Buchin S., Duboz G., Salmon J.-C. 2017. Lactobacillus delbrueckii subsp. lactis as a starter culture significantly affects the dynamics of volatile compound profiles of hard cooked cheeses. European Food Research and Technology. 243, 1943-1955.
- Buchin S., Dupont D., Beuvier E., Tessier L., Duboz G., Bérodier F., Pochet S., Thénard V. & Noël Y. 2005. La qualité des fromages est-elle affectée par le remplacement du concentré azoté en système autonome d’alimentation ? 12èmes Rencontres Recherches Ruminants, 7 et 8 décembre 2005, Paris.
Buchin S., Jeannin S., Arnould C., Palme R., Dufrene F., Beuvier E. 2021. How do oxidoreduction conditions affect the balance of volatile compounds produced by lactic acid bacteria in a curd-based medium ? 16th Weurman on line, May 4-6, 2021.
- Buchin S., Salmon J.C., Duboz G., Faurie F., Palme R., Duployer M.H. 2012. Composition du lait (taux protéique) et paramètres technologiques (levains thermophiles, température en cuve) affectent la composition des fromages PPC. Assemblée générale du Centre Technique des Fromages Comtois, 12 mars 2012, Chaffois, France.
- Cachon R., Gavoye S., Roussel C., Gaudu P., Beuvier E. 2015. Activités réductrices des bactéries lactiques dans les procédés fromagers. Revue des Industries Alimentaires et Agricoles novembre-décembre, 30-31.
- Charlet M. 2008. Dynamiques de croissance de S. thermophilus, Lactobacillus. delbrueckii et Lactobacillus helveticus dans les fromages à pâte pressée cuite pendant la phase d'acidification sous presse. Thèse de doctorat en Sciences des aliments, Université de Bourgogne, 237 p.
- Charlet M., Duboz G., Faurie F., Le Quéré J.-L., Berthier F. 2009. Multiple interactions between Streptococcus thermophilus, Lactobacillus helveticus and Lactobacillus delbrueckii strongly affect their growth kinetics during the making of hard cooked cheeses. International journal of Food Microbiology 131, 10-19.
- Demarigny Y., Beuvier E., Dasen A., Duboz G. 1996. Influence of raw milk microflora on the characteristics of Swiss-type cheeses. I. Evolution of microflora during ripening and characterization of facultatively heterofermentative lactobacilli. Lait 76, 371-387.
- Demarigny Y. 1997. Rôle de la flore naturelle du lait cru et de paramètres technologiques (teneur en sel et température d'affinage) sur l'évolution des caractéristiques biochimiques, microbiologiques et sensorielles des fromages à pâte pressée cuite. Thèse de Doctorat en Sciences des aliments, Université de Bourgogne, 184 p.
- Demarigny Y., Beuvier E., Buchin S., Pochet S., Grappin R. 1997. Influence of raw milk microflora on the characteristics of Swiss-type cheeses: II. Biochemical and sensory characteristics. Lait 77, 151-167.
- Gagnaire V., Piot M., Mollé D., Jardin J., Pezennec S., Ferré A., Desmars E., Duboz G., Buchin S. 2009. Combination of lactobacilli strains can modulate the anti-hypertensive activity in hard cooked cheeses. 4th IDF Dairy Science and Technology Week, 20-24th April, Rennes, France.
- Hurtaud C., Buchin S., Bérodier F., Duboz G., Beuvier E. 2012. Effet de combinaisons d’aliments riches en acides gras oméga 3 sur le profil en acides gras du lait et les caractéristiques physico-chimiques et sensorielles d’un fromage de type pâte pressée cuite. 19èmes Rencontres Recherches Ruminants, 5 et 6 décembre 2012, Paris.
- Hurtaud, C., Peyronnet, C., Lamy, J.-M., Duboz, G., Buchin, S., Bérodier, F., Beuvier, E., Brunschwig, P., 2014. Effets du tourteau de colza sur la composition du lait de vache et la qualité du fromage. 21ème Rencontres Recherches Ruminants, 3-4 décembre 2014, Paris, France. Institut de l'Elevage - INRA pp 55-58.
- Hurtaud C., Vanbergue E., Buchin S., Duboz G., Beuvier E., Guillevic M., Mourot J. 2015a. Effet de différentes formes d'apport d'omégas 3 sur le profil en acides gras des laits de vaches et les propriétés sensorielles des fromages et des beurres. Journées Francophones de Nutrition 9-11 décembre 2015, Marseille.
- Hurtaud, C., Peyronnet, C., Tormo E., Lamy, J.-M., Duboz, G., Buchin, S., Bérodier, F., Beuvier, E., Quinsac A., Brunschwig, P. 2015b. Effect of rapeseed meal on milk and cheese quality. 14th International Rapeseed Congress, 5-9 july 2015, Saskatoon, Canada.
- Jeanson S. 2000. La maturation du lait dans la fabrication de fromages à pâte pressée cuite : le rôle des lactocoques. Thèse de Doctorat en Sciences des aliments, Université de Bourgogne, 201 p.
- Jeanson S., Berthier F., Grappin R., Beuvier E. 2003. Heat resistance of wild Lactococcus lactis strains under a thermal gradient of cooked cheese, in milk and in minicheeses. Lait 83, 379-396.
- Lamprell H. 2003. Production des entérotoxines dans les fromages en fonction de la diversité phénotypique et génétique des souches de Staphylococcus aureus. Thèse de Doctorat en Sciences des aliments, Université de Bourgogne, 192 p.
- Munier E. 2023. Maîtrise de la fermentation butyrique par la microflore lactique réductrice. Thèse de doctorat, Université Bourgogne-Franche-Comté. 245 p.
- Petitpas F., Paysant B., Duboz, G. Dufrene, F. Gavoye S., Beuvier E. 2018. Oxidoreduction potential and O2 monitoring during the early steps of cheesemaking. 10th Cheese symposium, 4-6 avril 2018, Rennes, France.
- Vanbergue E., Hurtaud C., Peyrault J.-L., Beuvier E., Duboz G., Buchin S. 2018. Effects of n-3 fatty acid sources on butter and hard cooked cheese technological properties and sensory quality. International Dairy Journal 82, 35-44.
